Safety switch



May 12, 1925.-

0. T. SWEET SAFETY SWITCH Original Filed Feb. 17, 1919 WW j I I I I fizzleizior v fllz'wr I 5100a Patented May 12, 1925.

UNITED STATES OLIVER T. SWEET, OF ST. LOUIS, MISSOURI.

SAFETY SWITCH.

' Original application filed February 17, 1919, Serial No. 277,421.

' 6, 1921. Serial No. 467,478.

To all whom it may concern:

Be it known that I, OLIVER T. SWEET, a citizen of the United States, residing at St. Louis, Missouri, have invented a'certain new and useful Improvement in Safety Switches, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specification.

My invention relates generally to electric switches, and more particularly to switches of the knife-blade type, the present application being a division of an application filed by me February 17, 1919, Serial No. 277,421.

The objects of my invention are, to provide a switch having its contacting members arranged within a housing which is closed on all sides and is provided with closure means movably mounted on the cover of said housing and cooperating with the handle of the switch so that the openings in the cover plate and through which said handle operates are closed at all times by said closure means.

Further'objects of my invention are to provide a switch in which the blade is operable to simultaneously break contact with both terminal contacts and is adapted ito move away from said contacts the prescribed distance required by the regulationspertaining to the installation of electrical devices in buildings.

Another object of my invention is to provide a switch, the contact establishing parts of which are normally inaccessible so that a person operating the same is protected from electrical discharges and which switch is of simple construction and highly ellicient 1n operation. 7 i

In the drawings Figure 1 is a perspective view of the switch housing showing the movable closure member mounted thereon.

. Figure 2 is a vertical cross section of said switch.

Figure 3 is a transverse vertical cross section taken on line 33 of Figure 2.

Figure 4 I is a horizontal cross section taken on line 4'4 of Figure 3.

Referring by numerals to the accompanying drawings, 10 represents a housing of porcelain or analogous insulating material,

28 provided for each knife-blade.

Divided and this application filed May said housing being preferably of rectangular shape. Arranged in said housing are one or more compartments or recesses 11. The top and bottom of each compartment is providedwith openings 11 .through which the terminals of the lines enter each conipartment 11. Contact plates 15 and 16 are locatedin each compartment and are designed to be connected to the terminals of the lines by-means of screws or like fastening means 17 which are screw-seated in said plates. Contact plate 15 is arranged in the upper portion of each compartment and is supported therein by a screw 18 seated in the rear wall of housing 10 and engaging the lower end of said contact plate. Contact plate 16 is held in the lower portion of each compartment by ascrew 19 seated in the rear wall ofsaid housing and having its threaded end engaging the upper end of contact plate 16. I

1 Adjoining contact plate 15 is a U-shaped contact member 20 and adjoining contactplate 16 is a U-shaped contact member 21. These contact members are preferably held in position by screws 18 and 19 so that said contact members are electrically connected to the terminals of the lines through their respective contact plates 15 and 16. The ends of U-shaped contact members 20 and 21 are bent' inwardly soas to yieldingly engage the ends of knife-blade 2 which supported in each compartment by a pair of links 24. These links are pivotally mounted in stationary supports 25 'arried by the rear wall of housing 10 and the free ends of said links are pivotally connected to the switch blade 22.

A handle 26 is arranged exteriorly of said housing and has fingers or projections 28 which project inwardly into each compartment through slots 27 vertically disposed in the cover plate '21 which forms the front wall of said housing. The inner ends of these fingers are connected to corresponding knife-blades 22, there being a projection Links 21 are preferably of equal length and constitute a parallelogrammatic support for kmt'cblades 22 whereby when handle 26 is operated, blades 22 are moved outwardly and by virtueof their pivotal mounting on the free ends of links 24, each blade 22 will be equidistant from its corresponding members 20 and 21 so that the circuit is broken simultaneously at both terminals. Housing 10 is of suflicient depth and links 24 of proper length to permit switch blade 22 to be moved the predetermineddistance from contact members 20 and 21. i The upper ends of slots 27 are united by a horizontally disposed slot or opening 27 which is of suflicient size to permit the passage of handle 26 therethrough when attaching or detaching cover plate 27 to or from housing 10. A closure plate 29 is slidably mounted on cover 27 by means of vertical guideways 30 removably secured to said cover on each side of plate 29. A horizontally disposed opening 31 isiformed in plate 29 to accommodate the outwardly projecting handle 27. j

When handle 26 is operated. to open the circuit, said handle and the switch blades 22 are moved downwardly and outwardly to occupy positions shown in dotted lines in Figure 2. The downward movement of handle 26 causes the plate 29 to slide downwardly in guideways 30 so that the upper portion of said plate will be positioned against and close the horizontal opening 27 and the upper portions of vertical slots 27*. Plate 29 extends upwardly a'sufiicient distance to maintain openings 27 and 27 closed at all times so that the compartments in which contact members and the switch blades are mounted are rendered inaccessible, thereby eliminating any danger of injury to a person from electrical discharges or fire caused thereby.

The mounting of switch blade 22 by the use of pivotally supported links 24, provides means whereby the switch blade is maintained in position which is parallel with terminal contacts 20 and 21, so that the switch blade 22 engages and disengages both of said terminal contacts simultaneously.

Links 24 do not form part of the electrical circuit and arenot connected therewith; consequently when blade 22 is disengaged :Erom contact members 20 and 21 all electrical connection between said blade and the electrical circuit ceases-and the blade is dead or inactive. v

A switch constructed according to my in- .vention is quick and positive in its action,

and canbe-safely;

has few operating ,parts, operated.

I claim:.

1. ln a safety switch construction, the combination of an insulation housing hav ing a plurality of separate compartments, a pair of stationary contact members in each compartment, a pair of links pivotally supported in each compartment, a switch blade pivotally' mounted on the free ends of said links and movable into simultaneous engagement with both of saidcontact members, a closure plate for said housing, said plate being provided with vertically dis posed slots, a handle arranged exteriorly of said housing andhaving fingers projecting inwardly through said slots into said compartments for engaging said blades, and a sliding plate having cooperative engagement with said handle and contacting with said closure plate whereby the slots formed therein are closed at all times.

2. 'In a safety switch construction, combination of an insulation housing having a plurality of separate compartments, a pair of stationary contact members in each compartment, a pair of links (pivotally supported in each compartment, a switch blade pivotally mounted on the free ends of said links and movable into simultaneous engagement with both of said contact members, a closure plate for said housing, said plate being =provided with vertically disposed slots, a handle arranged exteriorly of said housing and having fingers projecting inwardly through said slots into said compartments for engaging said blades, a sliding plate having cooperative engagement with said handle and contacting with said closure plate whereby the slots formed therein are closed at all times, and vertically disposed ihg the edges of said sliding plate and guiding it in its movement.

uides on said closure member for engag-' the l 3. In an apparatus of the class described,

terminal contact members arranged in each compartment, a switch blade in each compartment cooperating with said contact members, a handle arran ed exteriorly of said housing and havin gers projecting into each compartment fixed to each switch blade and movable in vertical plane, pivotal means for movably supporting said switch blade in the housing whereby said switch blade is movablein' parallel with the contact members, a cover plate for the housing, said cover plate having vertically disposed openings through which the fingers of said handle operate, and closure means slidably mounted on said cover plate and adapted to move in a vertical plane in co-operation with said handle and close the unoccupied lating material applied to the block over the recess therein, said cover plate being provided with a vertically disposed slot, a handle for operating the switch blade, said handle being located on the exterior of the cover plate and having a portion extending through the slot and secured to the switch blade and closure means for said slot mounted for vertical movement on said cover and movable co-operatively with said handle. 7

5. In an electric switch the combination of 'a housing provided with separate compartments, a plurality of contact members arranged in each compartment, a switch blade mounted in each compartment 'and movable in parallel with said contacts, a cover plate secured to said housing, an operating handle fixed to said blades and projecting outwardly through slots vertically arranged in said plate, guides secured to said plate, and vertically movable closure means slidably mounted in said guides and 3 L co-operating with saidhandle for closing said slots in said plate.

6. In an electric switch, the combination of an insulated housing provided with separate compartments, a pair of stationary contact members arranged in each compartment, a switch blade in each compartment adapted to simultaneously engage and disengage said contact members, a cover plate for said housing provided with vertically disposed slots, an insulation handle arranged outwardly of said plate and having fingers projecting inwardly through said slots and engaging said blades, and a vertically disposed closure member slidably mounted on said cover and having an opening for the accommodation of said handle, whereby said closure member moves in vertical plane on said plate when said handle is operated;

In testimony whereof I hereunto aflix my signature this 13th day of April, 1921.

OLIVER T. SVEET. 

